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Post by g3750 on Aug 30, 2024 2:35:54 GMT
Has anyone ever had a smoke generator catch fire?
If so, can you identify the cause?
George
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Post by bluelinec4 on Aug 30, 2024 4:13:54 GMT
You see George you should have bought one of those Aristo Craft ones I had for sale
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Post by ohrailfan on Aug 30, 2024 9:10:03 GMT
What locomotive was involved ??
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Post by healey36 on Aug 30, 2024 13:15:37 GMT
What locomotive was involved ?? I'm guessing this was one used in a furnace stack.
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Post by Adam on Aug 30, 2024 13:18:45 GMT
I'm wondering how that could happen and really only 2 things come to mind.
1. Not enough (or no) smoke fluid. If the wick is dry, I could see it catching fire maybe.
2. Someone put the wrong thing, like oil, in the stack.
I guess the electronics could short or something but I would think that would be incredibly rare.
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chuck
New Member
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Post by chuck on Aug 30, 2024 14:27:58 GMT
I've heavily modified MTH large scale Big Boy type smoke units and had one running so hot that the fluid ignited. Quite a sight when the heavy plume of white smoke suddenly ignites sending flames and sparks into the air! That was on a G Scale USA Trains Big Boy all die-cast metal so didn't hurt anything. Good times!!
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Post by g3750 on Aug 30, 2024 15:17:18 GMT
You see George you should have bought one of those Aristo Craft ones I had for sale
Funny. Very funny.
George
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Post by trainman9 on Aug 30, 2024 15:48:22 GMT
Has anyone ever had a smoke generator catch fire?
If so, can you identify the cause?
George
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Post by g3750 on Aug 30, 2024 21:05:56 GMT
Ok, here's the full story.
I have a large static smoke generator that has been used to supply smoke to 2 of the 4 stacks on my Open Hearth (the other 2 are dummies).
Since placing the Open Hearth on the layout, I noticed some circuits were not operating properly. I had some LED light circuits that stopped working. And when I turned on the big smoke unit, all the lights (even the ones that weren't supposed to) would start blinking. I was debugging some of these circuits - testing them independently - and realized that the fan on the smoke unit wasn't turning. This is an intake fan that drives smoke out of exhaust tube.
After removing the fan from the smoke unit, the problem became obvious - a broken wire. I got the wire soldered back onto the fan and put it back on the smoke unit.
In the meantime, I told another member of my NMRA division who also happens to be an electrician, what was going on. He figured out that there wasn't enough power for all the circuits. I went through the exercise of calculating the load on the Open Hearth in watts (calculated as V * amps). The original powersupply was a Meanwell LRS-150-12 (150 watts at 12VDC). These power supplies are safely operated at 75% of rated wattage. For that power supply, 75% would be 112.5 watts. Here are details regarding the electrical components in the Open Hearth:
I was surprised - the mill was really underpowered. That prompted me to buy a larger power supply, Meanwell LRS-350-12 (350 watts). At 75% we're talking about 260 watts.
I tested this power supply and it is putting out 12VDC. I hooked it up in the mill and connected the smoke unit.
At first, everything went well. Smoke was being produced and being moved out of the 2 stacks without incident. I was standing over the unit watching it operate. Suddenly I hear a "pop", and flame starts shooting up out of the exhaust port. I immediately cut power and held my breath to see if the flames would abate. Fortunately, they did.
I cannot figure out why this happened. The unit was adequately filled with the correct smoke fluid.
I'm really not comfortable with putting smoke units in a hard to reach space.
George
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Post by harmonyards on Aug 30, 2024 21:26:40 GMT
We need to know the exact cause of the flames. Was there a short of some kind that has no circuit protection, and a wire caused the fire? Did the smoke unit’s resistor get glowing cherry red, and that caused the ignition? ……Any smoke unit should have safe voltage operating range. Did you modify the smoke unit for your purpose? No harm nor foul if you did, but you may want to know what Ohm resistor, and what wattage you need for your specific “custom” project. So what’s the specifics of the smoke unit you used that failed?
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Post by g3750 on Aug 30, 2024 23:02:43 GMT
We need to know the exact cause of the flames. Was there a short of some kind that has no circuit protection, and a wire caused the fire? Did the smoke unit’s resistor get glowing cherry red, and that caused the ignition? ……Any smoke unit should have safe voltage operating range. Did you modify the smoke unit for your purpose? No harm nor foul if you did, but you may want to know what Ohm resistor, and what wattage you need for your specific “custom” project. So what’s the specifics of the smoke unit you used that failed? I completely agree. I hate things that go "bump in the night". There is absolutely an explanation for this and I want to know.
To answer your questions (as best I can): - To the best of my knowledge, there was no short. But then again, I might not know what I was looking at.
- I don't know if the resistor got cherry red, but I think that's plausible as a cause.
- I absolutely did not modify the smoke unit in any way. I even buy commercial power supplies because I want that extra layer of safety that comes from manufacturing standards and UL testing. I'm not going to mess with something I don't fully understand.
I removed this smoke unit from the model and plan to hook it up to the same power supply tomorrow for a retest. This will take place on my driveway.
At this point, I am pretty certain this smoke unit is not safe to operate on a layout.
George
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Post by healey36 on Aug 30, 2024 23:21:58 GMT
"This will take place on my driveway."
Probably a good move. Hopefully you can replicate the event and run down the problem. Frankly, I've no idea; I didn't realize smoke fluid was flammable (although I do understand most have a high mineral oil content).
From the smoke unit's description - "You must have a constant power source between 11 and 12V (anything over 12v risks meltdown of the unit)". Is it my imagination or is that a tight window for operation, i.e. you gotta have nearly 12V to operate, but don't dare go over that at risk of destroying the unit.
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Post by harborbelt70 on Aug 31, 2024 12:14:23 GMT
"This will take place on my driveway."Probably a good move. Hopefully you can replicate the event and run down the problem. Frankly, I've no idea; I didn't realize smoke fluid was flammable (although I do understand most have a high mineral oil content). From the smoke unit's description - "You must have a constant power source between 11 and 12V (anything over 12v risks meltdown of the unit)". Is it my imagination or is that a tight window for operation, i.e. you gotta have nearly 12V to operate, but don't dare go over that at risk of destroying the unit.
The closest I have ever come to a flame-out was when an AC regulator feeding power to a Lionel 6 Ohm smoke unit failed causing full track power to go to the smoke unit and a very impressive but short-lived cloud of "smoke" appeared. Lionel had to "downgrade" these to 8 Ohms, which is the rating in most of the smoke unit resistors they use these days.
I know that RC boat enthusiasts use the sort of smoke generators described above and that some are used in G scale trains but I have never been tempted to try any of them.
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chuck
New Member
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Post by chuck on Aug 31, 2024 12:53:51 GMT
In my case it was cramming lots of heaters into a large smoke unit then powering them direct from the track. Use the PS2/3 to power the fan and a relay to power the heaters/ resistors.
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chuck
New Member
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Post by chuck on Aug 31, 2024 13:01:23 GMT
In my case it was cramming lots of heaters into a large smoke unit then powering them direct from the track. Use the PS2/3 to power the fan and a relay to power the heaters/ resistors. Harbor models makes a smoke unit for model boats that works good but it's plastic and those I don't trust. I stick with MTH and USA Trains die-cast smoke units. Aristo-Crafts design was mediocre at best...we gut them and then a USA Trains smoke unit will fit inside them.
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